External lubricant filter system for automatic transmissions

ABSTRACT

This invention provides an external lubricant filter system for automatic transmissions comprising a modified transmission lubricant pan assembly and an external spin on/off lubricant filter canister that is removably and sealably connected to the modified pan. The transmission pan is modified to include a filter adapter, a pick-up assembly, a discharge tube and inlet and outlet chambers. The filter adapter includes an externally threaded pipe nipple for removably receiving the filter canister, lubricant entry port and a lubricant inlet plenum for distributing the potentially contaminated lubricant to the inlet orifices of the filter canister, and a filter sealing surface. The lubricant pick up assembly delivers contaminated lubricant from the pan to the filter canister via the inlet chamber, and the entry port and plenum of the filter adapter. The discharge tube receives cleansed oil from the filter canister via the nipple and outlet chamber and delivers it to the inlet of the transmission&#39;s lubricant pump. In the preferred embodiment of this invention the filter canister is a conventional spin on/off oil filter. The modified pan may be formed by altering a factory stock pan, or preferably by altering an aftermarket product. Alternatively, the pan may be manufactured as an original equipment item that incorporates the novel features of this invention.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] This invention relates to fluid filters and more specifically tolubricant filters used for automatic transmissions such as those used inconjunction with internal combustion engines.

[0003] 2. Related Art

[0004] It is well established that the life of mechanical equipment isdependent on the quality of the lubricating fluid, i.e. the lubricant.The quality of lubricant, and in the case of automatic transmissions,the power transfer fluid, is assured by periodic lubricant replacementand thorough and continuous filtering of undesired foreign matter fromthe fluid.

[0005] The conventional approach for filtering the power transfer andlubrication fluid used in automatic transmissions is to include theentire filter system within the transmission housing. As a result,changing or cleaning a filter requires removing and replacing the lowerportion of the housing, i.e. the pan (or sump). This is a very timeconsuming process that is most frequently performed by professionalautomotive transmission specialists. In addition, because of thedifficulty and expense of changing these conventional filter systems,vehicle operators frequently delay filter changes well beyondrecommended mileage intervals, or even worse, they avoid changing thefilters altogether. This can lead to premature failure of thetransmission thus incurring repair or replacement costs of severalhundred or even thousands of dollars. Furthermore, by removing the pan,the risk of creating undesired transmission fluid leaks through adamaged pan gasket is substantially increased. Of course the occurrenceof such leaks is typically unknown until the transmission is operatedsufficiently to achieve normal operational temperatures. Thus theseleaks may go undetected for a long time. When the leak is finallydetected, the pan must be removed a second time, losing substantialquantities of the fresh fluid lubricant, and a new gasket must beinstalled. This process is time consuming, wasteful, environmentallydamaging, and costly.

[0006] Prior inventors are not known to have addressed this problem.Parker (U.S. Pat. No. 5,546,999) discloses new equipment forreplenishing the lubricant of an automatic transmission. Parker connectshis apparatus to an existing external fluid filter included in thetransmission cooling line of a tractor. He does not address the issue ofa convenient method of replacing automatic transmission fluid filters.

[0007] Ward U.S. Pat. No. 3,784,011) provides improved filtering ofautomatic transmission fluid by incorporating a magnetic medium in asupplemental filter included within the automatic transmission housing.

[0008] Holmes (U.S. Pat. No. 4,689,144) discloses a new supplementalfilter for automatic transmissions that incorporates both mechanical andmagnetic filtering elements in a disposable filter. The filter isprovided with fluid entry and exit spigots at opposite ends of acylindrical casing. This external filter is preferably placed in thecooling supply line before the transmission-cooling radiator. Holmes'filter is a new, unconventional design and thus not easily availablecommercially at this time. Furthermore, Holmes' filter is not integralwith the transmission housing and thus requires potentially unreliableconnection points and fluid transmission hoses. And finally, Holmes'filter is not easily replaced since it is of an unconventional designand is not adapted for a spin-on/spin-off installation and removal.

[0009] Thus, the objects of the extant invention are:

[0010] a. to provide a transmission lubricant filter that does notrequire removal of the transmission sump pan for its replacement,

[0011] b. to provide an transmission lubricant filter of theconventional spin-on/spin-off design that is external to thetransmission,

[0012] c. to provide a transmission filter that is convenientlyreplaced,

[0013] d. to provide a transmission fluid/lubricant filter that filtersall of the transmission lubricant that circulates through the lubricantpump,

[0014] e. to provide a more efficient transmission lubricant filter,

[0015] f. to provide a transmission filter that is easily adapted to anyautomatic transmission,

[0016] g. to provide a filtering concept that may be inexpensivelyincorporated into new transmission designs,

[0017] h. to provide a transmission filter that minimizes the loss oflubricant in the filter replacement process, and

[0018] i. to provide an automatic transmission filter that eliminatesthe leakage of fluid through the transmission sump pan gasket that mayresult from gasket damage during filter replacement.

SUMMARY OF THE INVENTION

[0019] As summarized in the previous discussion, there is a long feltand unfulfilled need for a means to conveniently, safely and effectivelyreplace automatic transmission lubricant filters. To meet this need, thepreferred embodiment of the extant invention provides an externallubricant filter system for automatic transmissions comprising amodified transmission lubricant pan assembly and an external spin on/offlubricant filter canister that is removably connected to the modifiedpan.

[0020] The transmission pan is modified to include a filter adapter inthe wall of the pan. The filter adapter includes an externally threadedpipe nipple and sealing surface for removably and sealably receiving thefilter canister. The adapter also includes a lubricant entry port and alubricant inlet plenum for distributing the potentially contaminatedlubricant to the inlet orifices of the filter canister.

[0021] The pan is further modified to incorporate a lubricant inletchamber and a lubricant outlet chamber, both secured to the interiorwall of the pan. This invention further includes a lubricant pick upassembly and a lubricant discharge tube. The lubricant pick up assemblydelivers contaminated lubricant from the pan to the filter canister viathe inlet chamber, and the entry port and plenum of the filter adapter.The discharge tube receives cleansed oil from the filter canister viathe nipple and outlet chamber and delivers it to the inlet of thetransmission's lubricant pump.

[0022] In the preferred embodiment of this invention the filter canisteris a conventional spin on/off oil filter. The modified pan may be formedby altering a factory stock pan, or preferably by altering anaftermarket product. Alternatively, the pan may be manufactured as anoriginal equipment item that incorporates the novel features of thisinvention

[0023] In use, this invention revolutionizes the changing of automatictransmission fluid filters. Rather than having to remove the pan fromthe transmission, the filter canister is merely rotated counterclockwiseto remove it from the pan while the pan remains attached to thetransmission housing. The replacement filter is simply threadedclockwise onto the cooperating pipe nipple and sealed to the adapter viathe seal supplied with the filter. In this fashion, the objectives ofthis invention are fully satisfied. The filter canister may be changedwithout removing the pan of the transmission, commercial off-the-shelffilters are used, all of the lubricant passing through the pump isfiltered and loss of fluid during filter changing operations isminimized. Additionally, this invention may be retrofitted to existingautomatic transmissions, or it may be incorporated in the originalmanufacture of the transmission.

[0024] These and many other features and attendant advantages of theinvention will become apparent, as the invention becomes betterunderstood by reference to the following detailed descriptions andaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0025]FIG. 1 is a left side view of the preferred embodiment of thisinvention showing all of the major features of this invention.

[0026]FIG. 2 is a forward view of this invention.

[0027]FIG. 3 is a top view of this invention.

[0028]FIGS. 4A and 4B are two isometric views of the filter adapter,FIG. 4A being viewed from the outside, and FIG. 4B being viewed from theinside.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0029]FIGS. 1, 2 and 3 show the salient and novel features of thisinvention of an external lubricant filter system 1 for automatictransmissions having a lubricant pump. The preferred embodiment of thisinvention comprises a modified transmission lubricant pan assembly 10and an external spin on/off lubricant filter canister 20. The filtercanister is removably and sealably connected to the modified pan. Panassembly 10 includes wall 11 having internal and external surfaces 12,13. The pan assembly also includes filter adapter 14 fixedly securedwithin the pan's wall between the internal and external surfaces.Referring now to FIGS. 4A and 4B adapter 14 further includes externallythreaded pipe nipple 15, plenum 16, filter sealing surface 19 andlubricant entry port 50. Filter canister 20 is sealed to the pan withits integral seal 21 bearing against seal surface 19 on adapter 14. Panassembly 10 farther includes inlet chamber 17 and outlet chamber 18,both fixedly attached to the internal surface of the wall of the pan.

[0030] Continuing reference to FIGS. 1,2 and 3, the pan assembly furtherincludes lubricant pick up assembly 30 and lubricant discharge tube 40.Pick up assembly 30 includes cup portion 31, pick up tube 32, and flangeportion 34. The flange portion is fixedly, sealingly and cooperativelyconnected to inlet chamber 17 via bolts 38 and sealed with flange gasket36.

[0031] Discharge tube 40 includes lower and upper ends 41, 45. The lowerend is fixedly, sealingly and cooperatively attached to outlet chamber18 and the upper end is fixedly, sealingly and cooperatively attached tothe inlet of the transmission lubricant pump which is common to allautomatic transmissions (this pump is not shown in the figures). Lowerand upper ends 41, 45 of the discharge tube have integral shoulders 42and 46 respectively. Lower shoulder 42 urges lower discharge tube seal43 against outlet chamber 18 to assure a leak free seal. Upper shoulder46 similarly urges upper discharge tube seal 47 against the inlet portof the transmission's lubricant pump, also assuring a leak free seal.

[0032] In operation, and continuing reference to FIGS. 1, 2 and 3,lubricating fluid 100 is withdrawn from the transmission pan/sump 10 bythe transmission lubrication pump via discharge tube 40. By this actionof the pump, potentially contaminated lubricant is brought to filtercanister 20 via pick-up assembly 30, inlet chamber 17, adapter lubricantentry port 50, and adapter plenum 16. Cleansed oil leaves the filtercanister through pipe nipple 15 via outlet chamber 18 and is thendelivered to the inlet of the pump by discharge tube 40.

[0033] In the preferred embodiment of this invention the filter is aconventional spin on/off oil filter such as are commercially availablefrom Hastings™, Purolator™, Fram™ and the like. The modified pan may beformed by altering a stock factory pan, or preferably by altering anaftermarket product, such as a cast aluminum pan manufactured by TCIAutomotive, 151 Industrial Drive, Ashland, MS, 38603. This pan providesthe added benefits of having cooling fins. Alternatively, the pan may bemanufactured as an original equipment item that incorporates the novelfeatures of this invention.

[0034] The required alterations to the conventional pan include thefollowing:

[0035] a. Forming filter adapter 14 from aluminum stock. This adapter ismachined to provide a sealing surface for a standard commercial oilfilter and its integral gasket, to accept externally threaded pipenipple 15 and to provide plenum 16. Nipple 15 is formed by boring a ½inch hole along the axis of a ¾ inch diameter, externally threaded,steel rod.

[0036] b. Cutting a hole in the wall of the pan and welding the filteradapter into the opening thus provided so that it becomes integral withthe wall of the pan.

[0037] c. Forming the inlet and outlet chambers from aluminum sheetstock of about ¼ inch thickness by welding to the internal surface 12 ofthe pan's wall 11. These chambers are drilled to accept pick-up assembly30 and discharge tube 40.

[0038] d. Forming pick-up assembly as shown in FIGS. 1, 2 and 3 fromsteel tubing and sheet stock to form flange 34 portion and cup portion31. In the preferred embodiment, the pick-up assembly is formed byadding a short length of steel tubing with a flange to a stock oil pumppick-up tube. Two bolts 38 are used to attach the flange to the inletchamber. This joint is sealed by flange gasket 36.

[0039] e. Forming discharge tube 40, having lower and upper shoulders42, 46, from aluminum stock. Lower end 41 of the discharge tube isconnected to outlet chamber 18 via lower seal 43. This seal is urgedinto the outlet chamber by lower shoulder 42. In a similar fashion, theupper end of the discharge tube is sealed to the inlet of thetransmission lubricant pump by urging upper shoulder 46 against upperseal 47 which in turn sealingly presses into the inlet of the pump. Bothseals are conventional as used to seal internal transmission filters.

[0040] In use, this invention revolutionizes the changing of automatictransmission fluid filters. Rather than having to remove the pan fromthe transmission, the filter canister is merely rotated counterclockwiseto remove it from the pan while the pan is still attached to thetransmission housing. The replacement filter is then simply clockwisethreaded onto cooperating nipple 15 and sealed to adapter 14 via theseal supplied with the filter canister.

[0041] In this fashion, the objectives of this invention are fullysatisfied. The filter may be changed without removing the pan from thetransmission housing, commercial off-the-shelf filters may be used, allof the lubricant passing through the pump is filtered and loss of fluidduring filter changing operations is minimized. Additionally, thisinvention may be retrofitted to existing automatic transmissions, or itmay be incorporated in the original manufacture of the transmission.

[0042] An alternative embodiment of this invention may incorporate aremotely mounted external oil filter. That is to say that rather thanmounting the filter canister directly in the wall of the pan, the filteris mounted on the frame of the vehicle, perhaps within the enginecompartment of the vehicle. In this embodiment (not pictured), thefilter canister is attached to a cooperating mounting adapter havinglubricant inlet and outlet ports. The mounting adapter ports in turn areconnected via conventional hydraulic fluid hoses to cooperating portsformed into the wall of the pan. In this manner, potentiallycontaminated fluid is delivered to the remotely mounted filter andcleansed fluid is returned to the inlet of the transmission pump. Thisembodiment enjoys the benefits of a more easily accessible filtercanister but suffers the disadvantage of lengthy connecting hoses andassociated line pressure losses.

[0043] Although this invention has been described above with referenceto particular means, materials and embodiments, it is to be understoodthat the invention is not limited to these disclosed particulars, butextends instead to all equivalents within the scope of the followingclaims.

I claim:
 1. An external lubricant filter system for automatictransmissions having a lubricant pump, said system comprising: amodified transmission lubricant pan assembly and an external spin on-offlubricant filter canister removably connected to said modified pan. 2.An external lubricant filter system for automatic transmissionsaccording to claim 1 wherein said modified transmission pan assemblyincludes a wall having internal and external surfaces and a filteradapter fixedly secured within the wall between the internal andexternal surfaces, said adapter further including an externally threadedpipe nipple, a lubricant entry port, a plenum and a filter canistersealing surface.
 3. An external lubricant filter system for automatictransmissions according to claim 2 wherein said pan assembly furtherincludes an inlet chamber and an outlet chamber both fixedly attached tothe internal surface of the wall of said pan.
 4. An external lubricantfilter system for automatic transmissions according to claim 2 whereinsaid pan assembly further includes a lubricant pick up assembly and alubricant discharge tube.
 5. An external lubricant filter system forautomatic transmissions according to claim 4 wherein said pick upassembly includes a cup portion, a pick up tube, and a flange portion,the flange portion being fixedly, sealingly and cooperatively connectedto said inlet chamber.
 6. An external lubricant filter system forautomatic transmissions according to claim 4 wherein said discharge tubefurther includes lower and upper ends, the lower end having a lowershoulder and being fixedly and sealingly attached to the outlet chamber,and the upper end having an upper shoulder and being fixedly, sealinglyand cooperatively attached to the transmission lubricant pump.